Coupling of communications signals to a power line

ABSTRACT

In one embodiment, a device for coupling communications signals onto a medium-voltage power line includes a first connector, a second connector and one or more components. The first connector is adapted to couple to a low-voltage communications line. The second connector is adapted to couple to a surge arrester. The one or more components are operable to substantially match the impedances between the surge arrester and the low-voltage communications line.

RELATED APPLICATION

This application claims the benefit under 35 U.S.C. § 119(e) of U.S.Provisional Application Ser. No. 60/700,038 filed Jul. 15, 2005.

TECHNICAL FIELD

This invention relates generally to communications networks and inparticular to a system and method for improved coupling ofcommunications signals to a power line.

BACKGROUND

Power systems utilize a variety of electrical devices and connectors todeliver electricity from a power station or generator to customers. Somepower systems utilize a three-tiered approach that utilizes high-voltagepower lines with voltages in the range from approximately 60 kV to 100kV, medium-voltage power lines with voltages in the range fromapproximately 4 kV to 60 kV, and low-voltage power lines with voltagesin the range from approximately 90V to 600V.

In these three-tiered power systems, high-voltage power lines typicallyconnect a power station or generator to a substation. The substationserves a particular area such as a neighborhood and includes atransformer to step-down the voltage from high voltage to mediumvoltage. Typically, multiple sets of medium-voltage power lines connectthe substation to local distribution transformers. The distributiontransformers typically serve the customers in close proximity to thedistribution transformer and step-down the voltage from medium voltageto low voltage for use by the customers.

The power lines used to deliver electricity to customers have also beenused to transmit and receive communications signals. For example, powerlines have been used by utility companies to transmit and receivecommunications signals to monitor equipment and to read meters. Powerlines have also been used to provide broadband communications forcustomers. Various techniques have been developed to couple broadbandcommunications signals to medium-voltage power lines. These broadbandcommunications signals typically occupy frequencies in the 2-50 MHzregion. One approach to coupling communications signals to thesemedium-voltage power lines is to use the intrinsic capacitance of metaloxide varistor (MOV) lightning arresters to couple a portion of thecommunications radio frequency signals onto medium-voltage power lines.Most MOV lightning arresters have a special device attached to thebottom of the arrester assembly to explosively disconnect the groundingwire in case of a current fault. This device usually consists of agrading resistor in parallel with an air-gap and small gunpowder charge.

SUMMARY OF THE INVENTION

In one embodiment, a device for coupling communications signals onto amedium-voltage power line includes a first connector, a second connectorand one or more components. The first connector is adapted to couple toa low-voltage communications line. The second connector is adapted tocouple to a surge arrester. The one or more components are operable tosubstantially match the impedances between the surge arrester and thelow-voltage communications line.

Particular embodiments of the present invention may provide one or moretechnical advantages. For example, certain embodiments of the presentinvention may provide improved transmission and throughput ofcommunications signals. As another example, in certain embodiments, thesize and placement of the coupling device may provide for relativelyquick and simple installation with little or no modifications toexisting equipment. In these embodiments, such relatively quick andsimple installation may allow for rapid deployment of communicationscoverage and/or rapid repair in the event of a localized surge orlightning strike. Certain embodiments of the present invention mayprovide one or more of these technical advantages at a relatively lowcost.

Certain embodiments of the present invention may improve the couplingefficiency for systems utilizing MOV lightning arresters with explosivedisconnect devices. These disconnect devices have been shown to limitthe efficiency of communications signal transmission over medium-voltagepower lines. The arrester disconnect device can cause the frequencyresponse of a communications signal coupler to roll-off prematurely andlimit or prevent the use of lower frequencies between communicationsdevices. By bypassing this disconnect device at radio frequencies,certain embodiments of the present invention may reduce the seriesimpedance contribution of the disconnect device and thereby reduce oreliminate this performance problem.

In addition, certain embodiments may provide one or more other technicaladvantages some, none, or all of which may be readily apparent to thoseskilled in the art from the figures, descriptions, and claims includedherein.

BRIEF DESCRIPTION OF THE DRAWINGS

To provide a more complete understanding of the present invention andthe features and advantages thereof, reference is made to the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 illustrates a portion of an example power-line communicationssystem, according to a particular embodiment;

FIG. 2 illustrates an example regenerator unit included in certainembodiments of a power-line communications system;

FIG. 3 illustrates an example customer-access unit included in certainembodiments of a power-line communications system;

FIG. 4 illustrates an example regenerator/customer-access unit includedin certain embodiments of a power-line communications system;

FIG. 5 illustrates a portion of an example power-line communicationssystem including an example surge arrester and an example coupler,according to a particular embodiment;

FIG. 6 illustrates a circuit diagram of a portion of an examplepower-line communications system, according to a particular embodiment;

FIG. 7 illustrates a component diagram of an example coupler, accordingto a particular embodiment;

FIG. 8 illustrates a portion of an example power-line communicationssystem including an example surge arrester, an example disconnectdevice, an example parallel bypass including an example bypasscapacitor, and an example coupler, according to a particular embodiment;

FIG. 9 illustrates a circuit diagram of an example medium-voltage powerline disconnect device;

FIG. 10 illustrates a circuit diagram of an example medium-voltage powerline disconnect device with an example parallel bypass including anexample bypass capacitor, according to a particular embodiment;

FIG. 11 illustrates a circuit diagram of a portion of an examplepower-line communications system, including an example disconnect deviceand an example parallel bypass including an example bypass capacitor,according to a particular embodiment;

FIG. 12 illustrates a component diagram of a coupler, including a bypasscapacitor, according to a particular embodiment;

FIG. 13 illustrates a component diagram of a coupler, including a bypasscapacitor and impedance matching components, according to a particularembodiment;

FIG. 14 illustrates a portion of an example power-line communicationssystem including an example surge arrester, an example disconnectdevice, an example parallel bypass, and an example coupler, according toa particular embodiment; and

FIG. 15 illustrates a circuit diagram of a portion of an examplepower-line communications system, including an example disconnect deviceand an example parallel bypass, according to a particular embodiment.

DESCRIPTION OF EXAMPLE EMBODIMENTS

It should be understood at the outset that although example embodimentsof the invention are illustrated below, the present invention may beimplemented using any number of techniques, whether currently known ornot. The present invention should in no way be limited to theillustrated embodiments, drawings, and techniques. Additionally, thedrawings are not necessarily drawn to scale.

FIG. 1 illustrates a portion of an example power-line communicationssystem, indicated generally at 10, utilizing medium-voltage power linesto carry communications signals. In certain embodiments, power-linecommunications system 10 may function to provide one or more customerswith access to a wide area network (WAN). For example, power-linecommunications system 10 may function to provide one or more customerswith access to data services, video services,voice-over-Internet-Protocol (VoIP), or plain-old-telephone service(POTS). As another example, the communications signals may representupstream and/or downstream traffic at transmission rates of at least 200kbps. In a particular example, power-line communications system 10 mayfunction to provide one or more customers with access to the Internet.In certain embodiments, power-line communications system 10 may includemedium-voltage phase line 12, neutral line 14, surge arrester 16, andcommunications device 18.

Medium-voltage phase line 12 represents a transmission power lineoperable to conduct medium-voltage electricity. In certain embodiments,medium-voltage phase line 12 may be an overhead transmission line. Inparticular embodiments, medium-voltage phase line 12 may conduct analternating current (AC) of electricity between approximately 4 and 60kilovolts. In embodiments of power-line communications system 10including neutral line 14, neutral line 14 may represent a power line ofthe same or similar structure and capability as medium-voltage phaseline 12.

Communications device 18 may broadly represent a device for receivingand/or transmitting communications signals. For example, in certainembodiments, communications device 18 may represent a regenerator unit,a customer-access unit, or a combination regenerator/customer-accessunit. In certain embodiments, communications device 18 couples tomedium-voltage phase line 12, as described below, and may also couple toneutral line 14 and/or a ground connection through the use of conductor28. Conductor 28 may represent any appropriate wire or cable, such as,for example, a standard #4 or #6 AWG solid copper wire. Exampleembodiments of communications device 18 are describe below in relationto FIGS. 2-4.

Surge arrester 16 may represent a device for electrically couplingmedium-voltage phase line 12 to neutral line 14 and/or a groundconnection in the event of an over-voltage condition. In certainembodiments, surge arrester 16 may represent a metal oxide varistor(MOV) lightning arrester. For example, surge arrester 16 may representan Ohio Brass HD Arrester, 18 KV class, or any other appropriatelightning arrester for use with medium-voltage phase line 12.

In operation, communications system 10 may enable one or more end-usersto transmit and/or receive communications signals using medium-voltagephase lines 12. In certain embodiments, communications signals arecoupled to medium-voltage phase line 12 and carried to and/or from oneor more communications devices 18. In certain embodiments, thecommunications signals are transmitted from medium-voltage phase line 12to communications device 18 using the intrinsic capacitance of a metaloxide varistor (MOV) arrester. In certain embodiments, communicationssystem 10 may enable multiple end-users to transmit and/or receivebroadband communications signals. For example, the broadbandcommunications signals may represent upstream and/or downstream trafficat transmission rates of at least 200 Kbps.

Although, certain aspects and functions of the present invention aredescribed in terms of receiving and/or transmitting communicationssignals, in certain embodiments, these functions may be reversed, as maybe appropriate, without departing from the spirit and scope of thepresent invention.

FIG. 2 illustrates an example regenerator unit 18 a included in certainembodiments of power-line communications system 10. In the exampleshown, regenerator unit 18 a includes housing 100, two modems 102,switch 104, and wireless access point 106.

Housing 100 operates to create an enclosed area containing the elementsof regenerator unit 18 a. In certain embodiments, housing 100 mayoperate to protect the elements of regenerator unit 18 a and to simplifythe installation of regenerator unit 18 a by keeping the elements ofregenerator unit 18 a together with the appropriate internalconnections. In certain embodiments, housing 100 may also providestructural support for the elements of regenerator unit 18 a and mayprovide electrical insulation between certain elements of regeneratorunit 18 a. In certain embodiments, housing 100 may represent a weatherproof, sealed container to enclose moisture sensitive elements ofregenerator unit 18 a. For example, housing 100 may include a hingedaluminum case with one or more rubber seals and threaded closures. In aparticular embodiment, housing 100 may have dimensions of less than 12inches in height, width, and depth. For example, housing 100 may be aweatherproof Scientific-Atlanta CATV Line Extender Housing. However, anyappropriate container may be used to contain the elements of regeneratorunit 18 a and/or the elements of regenerator unit 18 a may be containedindividually or in other combinations.

Modems 102 are electrically coupled to medium-voltage power line 12. Inoperation, modems 102 demodulate communications signals received frommedium-voltage power line 12 and/or modulate communications signals fortransmission on medium-voltage power line 12. Thus modems 102 representany appropriate hardware and/or controlling logic for modulating and/ordemodulating communications signals. In certain embodiments, modems 102receive and transmit RF signals. For example, modems 102 may represent aHomePlug Powerline Alliance (HPA) compliant modem or a UniversalPowerline Association (UPA) compliant modem. In certain embodiments,modems 102 may transmit and receive communications signals through acoaxial connection using an F-connector. In a particular embodiment,modems 102 may represent NetGear modems. Although, in certainembodiments, multiple modems 102 may be the same, this is not necessary.

Switch 104 may couple to modems 102 and wireless access point 106. Inoperation, switch 104 operates to receive and transmit digitalcommunications signals among the elements of regenerator unit 18 a.Thus, switch 104 may represent any appropriate hardware and/orcontrolling logic for directing the flow of digital communicationssignals among multiple elements of regenerator unit 18 a. For example,in certain embodiments, switch 104 may be a router, a hub, an Ethernetswitch, or a network processor. In certain embodiments, switch 104 mayhave an IP address that is unique within power-line communicationsnetwork 10.

In embodiments of regenerator unit 18 a including wireless access point106, wireless access point 106 operates to transmit and/or receivewireless communications signals. Thus wireless access point 106represents any appropriate hardware and/or controlling logic fortransmitting and/or receiving wireless communications signals. Incertain embodiments, wireless access point 106 may transmit and/orreceive wireless communications signals using an IEEE 802.11 standardprotocol. In a particular embodiment, wireless access point may be aD-Link wireless access point coupled to switch 104 through the use of10/100 base-T connectors.

In operation, regenerator unit 18 a receives communications signals frommedium-voltage power line 12, demodulates the received communicationssignals, re-modulates at least a portion of the received communicationssignals, and transmits the re-modulated communications signals tomedium-voltage power line 12. Thus, in certain embodiments, regeneratorunit 18 a operates to allow communications signals to travel greaterdistances along medium-voltage power line 12 by preventing excessattenuation. Accordingly, regenerator unit 18 a may operate to receivecommunications signals from a medium-voltage power line 12, amplify thecommunications signals and/or filter out certain types of signal noise,and then re-transmit the communications signals back on themedium-voltage power line 12. In certain embodiments, wireless accesspoint 106 may operate to provide wireless access to one or more wirelessdevices. For example, wireless access point 106 may operate to create awireless “hot spot,” by providing wireless Internet access to one ormore wireless devices. In particular embodiments, wireless access point106 may operate to allow for monitoring and/or modifying the operationof regenerator unit 18 a.

FIG. 3 illustrates an example customer-access unit 18 b included incertain embodiments of power-line communications system 10. In theexample shown, customer-access unit 18 b includes housing 100, twomodems 102, switch 104, wireless access point 106, and control module112.

Housing 100, switch 104, and wireless access point 106 included incustomer-access unit 18 b may be the same or substantially similar toswitch 104 and wireless access point 106 described above with regard toregenerator unit 18 a. For example, housing 100 may operate to protectthe elements of customer-access unit 18 b and may operate to simplifythe installation of customer-access unit 18 b by keeping the elements ofcustomer-access unit 18 b together with the appropriate internalconnections. In certain embodiments, housing 100 may also providestructural support for the elements of customer-access unit 18 b and mayprovide electrical insulation between certain elements ofcustomer-access unit 18 b. As another example, switch 104 may representany appropriate hardware and/or controlling logic for directing the flowof digital communications signals among multiple elements ofcustomer-access unit 18 b. In certain embodiments, switch 104 may be arouter, a hub, or an Ethernet switch.

Modems 102 a and 102 b included in customer-access unit 18 b may be thesame or substantially similar to modems 102 described above with regardto regenerator unit 18 a, with the exception that modem 102 b mayelectrically couple to a low-voltage power line. In operation, modem 102a demodulates signals received from medium-voltage power line 12 and/ormodulates communications signals for transmission on medium-voltagepower line 12; and modem 102 b demodulates signals received from alow-voltage power line and/or modulates communications signals fortransmission on a low-voltage power line. Thus modems 102 represent anyappropriate hardware and/or controlling logic for modulating and/ordemodulating communications signals.

Control module 112 operates to control the operation of certain aspectsof customer-access unit 18 b. In certain embodiments, control module 112may serve as a firewall, a router, and/or an agent. For example, controlmodule 112 may collect and store information related to the quantity andtype of communication signals received and transmitted bycustomer-access unit 18 b. As another example, control module 112 mayprevent particular portions of communications signals received bycustomer-access unit 18 b from being transmitted by customer-access unit18 b. In certain embodiments, control module 112 may operate to couplethe elements of customer-access unit 18 b associated with portions oftwo logical networks. In certain embodiments, control module 112 maycouple elements of customer-access unit 18 b associated with a wide areanetwork (WAN) and with a local area network (LAN). For example, controlmodule 112 may couple modem 102 a associated with a WAN, such as a WANformed at least in part by communications network 10, to modem 102 bassociated with a LAN, such as a LAN associated with a customer. Incertain embodiments, control module 112 may serve to control and/orlimit the flow of communications signals between the WAN and the LAN. Incertain embodiments, control unit 112 may operate to provide remotecontrol and/or remote monitoring of certain aspects of customer-accessunit 18 b. For example, control module 112 may operate to provide remotecontrol and/or remote monitoring through the use of simple networkmanagement protocol (SNMP) or through a terminal emulation program suchas Telnet. In certain embodiments, control module 112 may operate as anSNMP agent to allow a remote administrator to monitor and/or control oneor more parameters related to modems 102 and/or the communicationssignal traffic within customer-access unit 18 b. In certain embodiments,control module 112 may include encryption algorithms to restrict accessto the control features and or to restrict access from the WAN to theLAN.

In operation, customer-access unit 18 b may receive communicationssignals from a medium-voltage power line 12, demodulate the receivedcommunications signals, re-modulate at least a portion of the receivedcommunications signals, and transmit the re-modulated communicationssignal to a low-voltage power line.

Although customer-access unit 18 b has been described as receivingcommunications signals from medium-voltage power line 12 andtransmitting communications signals to a low-voltage power line,customer-access unit 18 b may also receive communications signals from alow-voltage power line and transmit communications signals tomedium-voltage power line 12. In certain embodiments, wireless accesspoint 106 may operate to create a wireless “hot spot,” by providingwireless Internet access to one or more wireless devices. In particularembodiments, wireless access point 106 may operate to allow formonitoring and/or modifying the operation of customer-access unit 18 b.

FIG. 4 illustrates an example regenerator/customer-access unit 18 cincluded in certain embodiments of power-line communications system 10.In the example shown, regenerator/customer-access unit 18 c includeshousing 100, two modems 102 a, one modem 102 b, two switches 104, onewireless access point 106, and one control module 112.

Housing 100, switch 104, wireless access point 106, and control module112 included in regenerator/customer-access unit 18 c may be the same orsubstantially similar to the same elements described above with regardto regenerator unit 18 a and customer-access unit 18 b. Modem 102 a mayoperate to electrically couple to a medium-voltage power line 12 andmodem 102 b may operate to electrically couple to a low-voltage powerline. In certain embodiments modem 102 a may be the same orsubstantially similar to modem 102 described with respect to regeneratorunit 18 a. Similarly, in certain embodiments, modem 102 b may be thesame or substantially similar to modem 102 b described with respect tocustomer-access unit 18 b. Thus modem 102, included inregenerator/customer-access-unit 18 c represents any appropriatehardware and/or controlling logic for modulating and/or demodulatingcommunications signals.

In operation, regenerator/customer-access-unit 18 c may operate toregenerate communications signals on a medium-voltage power line 12and/or provide one or more customers with access to communicationsnetwork 10. In certain embodiments, regenerator/customer-access-unit 18c may function as either a regenerator unit 18 a or a customer-accessunit 18 b. In a particular embodiment, regenerator/customer-access unit18 c may function as both a regenerator unit 18 a and a customer-accessunit 18 b. For example, regenerator/customer-access unit 18 c mayreceive communications signals from medium-voltage power line 12,selectively communicate a portion of the received communications signalsto a low-voltage power line, and selectively communicate a portion ofthe received communications signals to medium-voltage power line 12. Incertain embodiments, regenerator/customer-access unit 18 c may alsoreceive wireless signals through the use of a wireless access point 106.For example, wireless signals received by a wireless access point 106may include instructions for monitoring and/or modifying the operationof regenerator/customer-access unit 18 c. As another example, wirelesssignals received by wireless access point 106 may be transmitted to amedium-voltage power line 12 by a modem 102 a or may be transmitted to alow-voltage power line by modem 102 b. In certain embodiments, wirelessaccess point 106 may operate to create a wireless “hot spot,” byproviding wireless Internet access to one or more wireless devices.

FIG. 5 illustrates an example portion of a power-line communicationssystem 10. In the embodiment shown, power-line communications system 10includes medium-voltage phase line 12, neutral line 14, surge arrester16, communications device 18, coupler 20, conductors 22 and 28, ferrites24, and low-voltage communications line 26. In operation, communicationssignals are communicated between medium-voltage phase line 12 andcommunications device 18 through the use of surge arrester 16 andcoupler 20. In certain embodiments, conductor 22 may couple surgearrester 16 to neutral line 14 and/or a ground connection.

Conductor 22 may represent any appropriate wire or cable, such as, forexample, a standard #4 or #6 AWG solid copper wire. In embodimentsincluding conductor 22, one or more ferrites 24 may be coupled toconductor 22 so that the one or more ferrites substantially surround aportion of conductor 22. In operation, ferrites 24 may serve as alow-pass filter preventing (or attenuating) the transmission ofhigh-frequency signals through the portion of conductor 22 coupled tothe one or more ferrites 24. Although the embodiment shown includesferrites 24, in certain alternative embodiments, any suitable device maybe used to provide this filtering function.

Coupler 20 is a device that couples communications device 18 to surgearrester 16. In certain embodiments, coupler 20 is electrically coupledto communications device 18 through the use of low-voltagecommunications line 26. In certain embodiments, low-voltagecommunications line 26 may represent any appropriate single or multiconductor cable or wire. For example, in certain embodiments,low-voltage communications line may represent a coaxial cable, anEthernet cable, a telephone cable, or a serial cable. In certainembodiments, conductor 26 may represent two or more single or multiconductor cables and/or wires. In certain embodiments, coupler 20 iscoupled to surge arrester 16 through a direct conductive connection withsurge arrester 16. For example, in certain embodiments, coupler 20 iscoupled to surge arrester 16 through ground post 29 if arrester 16. Inparticular embodiments, coupler 20 may include a conductive portion thatmay include an opening large enough to slide over the ground post 29 ofsurge arrester 16. Coupler 20 may be positioned directly adjacent to (orintegral to) surge arrester 16, directly adjacent to (or integral to)communications device 18, and/or in any other appropriate position withrespect to communications device 18 and surge arrester 16.

In certain embodiments, coupler 20 may provide an impedance matchbetween medium-voltage phase line 12 (and/or surge arrester 16) andconductor 26 (and/or communications device 18). For example, in certainembodiments, coupler 20 may include one or more capacitors and one ormore impedance transformers to provide this impedance matching function.Further description of embodiments of coupler 20 including one or morecapacitors and one or more impedance transformers is provided below inrelation to FIG. 7. Although, certain embodiments of coupler 20 aredescribed herein as including one or more capacitors and one or moreimpedance transformers, in other embodiments coupler 20 may includeother appropriate components and/or techniques to provide this impedancematching function.

In certain embodiments, coupler 20 (or variations thereof, such ascoupler 120 identified below) may provide a means for bypassing anexplosive disconnect device, which may improve the coupling efficiency.Embodiments providing such bypass means are described further below inrelation to FIGS. 9-15.

FIG. 6 illustrates a circuit diagram of an example portion of power-linecommunications system 10. In the embodiment shown, power-linecommunications system 10 includes medium-voltage phase line 12, surgearrester 16, communications device 18, and a coupler 20. Surge arrester16 is coupled to communications device 18 through the use of coupler 20.In the embodiment shown, coupler 20 is connected to communicationsdevice 18 through the use of low-voltage communications line 26, whichincludes conductors 34 a and 34 b.

In the embodiment shown, coupler 20 includes an impedance transformer 30and a capacitor 32. As shown, conductor 34 a is coupled to thenon-common low-impedance winding of impedance transformer 30, whileconductor 34 b is coupled to the common winding of impedance transformer30 on both the primary and secondary. In certain embodiments, conductor34 b may also be coupled to neutral line 14 and/or a ground connection.As shown, in certain embodiments, the non-common winding of thehigh-impedance side of impedance transformer 30 is coupled to acapacitor 32, which is coupled to surge arrester 16.

In certain embodiments, medium-voltage phase line 12 (and/or surgearrester 16) may have an impedance in the range from 350-450 ohms andconductor 26 (and/or communications device 18) may have an impedance inthe range from 50-75 ohms. In certain embodiments, to match impedances,impedance transformer 30 may represent a transformer with a step-upratio in the range from approximately 5:1 to 9:1. For example, in aparticular embodiment, impedance transformer 30 may represent atransformer with a step-up ratio of approximately 8:1, such as forexample a Mini Circuits T8-1 transformer. In certain embodiments,capacitor 32 may have a capacitance in the range of 0.01 to 0.1microfarads and capacitor 32 may have a working capacity greater than300 volts. For example, in a particular embodiment, capacitor 32 mayrepresent a 0.047 microfarad 600 volt coupling capacitor. Althoughexample embodiments including impedance transformer 30 and capacitor 32have been described as having certain characteristics or ranges ofcharacteristics, any appropriate components may be used to match (orimprove the matching of) impedances within power-line communicationssystem 10 without departing from the spirit and scope of the presentinvention. In certain embodiments, for example, power-linecommunications system 10 and/or coupler 20 may include differentconnection topologies and/or different types of impedance transformers30. In a particular embodiment, certain functions of the presentinvention may be accomplished using a transmission line transformer.

FIG. 7 illustrates a component diagram of an example configuration ofcoupler 20, according to a particular embodiment. As shown, coupler 20includes impedance transformer 30, capacitor 32, base 40, and connectors42 and 44. Impedance transformer 30 and capacitor 32 operate asdescribed above in relation to FIG. 6.

Base 40 represents any appropriate structure for supporting thecomponents of coupler 20. For example, base 40 may represent a housingthat physically surrounds one or more components of coupler 20. Asanother example, base 40 may represent a substrate upon which certaincomponents may be positioned, such as a 1″×2″ printed circuit board. Inparticular embodiments, base 40 may include one or more protectivecoverings. For example, base 40 may include coverings adapted to provideweather and/or UV protection for certain components of coupler 20. In aparticular embodiment, base 40 may represent a printed circuit boardcoated with a first coat of Humiseal 1A20 Polyurethane and a second coatof Humiseal 1C49 Silicone.

Connector 42 represents a conductive connector adapted to electricallyconnect coupler 20 to communications device 18. In certain embodiments,connector 42 may connect coupler 20 to communications device 18 throughlow-voltage communications line 26. In a particular embodiment,low-voltage communications line 26 may represent a coaxial cable andconnector 42 may represent a coaxial connector, such as a BNC connectoror an F-connector.

Connector 44 represents a conductive connector adapted to electricallyconnect coupler 20 to surge arrester 16. In certain embodiments,connector 44 may connect coupler 20 to surge arrester 16 through the useof one or more conductive cables or wires. In other embodiments,connector 44 may connect coupler 20 to surge arrester 16 through groundpost 29 on surge arrester 16. For example, in the illustratedembodiment, connector 44 may represent a conductive material with anopening adapted to accept ground post 29 of surge arrester 16. Forexample, connector 44 may represent a metallic disk (or cylinder) with athru-hole that is approximately 0.375-0.400 inches in diameter. In theembodiment shown, connector 44 is positioned integral to base 40 suchthat, in operation, base 40 with connector 44 may slide over ground post29 of surge arrester 16 to establish a conductive contact with groundpost 29 and/or a retaining nut threaded onto ground post 29.

In embodiments including impedance transformer 30 and/or capacitor 32,impedance transformer 30 and/or capacitor 32 may be electricallyconnected in series between connector 42 and connector 44. In certainembodiments, base 40 may provide the electrical coupling betweencomponents of coupler 20. For example, in embodiments wherein base 40represents a printed circuit board, integrated conductors of base 40 mayprovide the electrical coupling.

FIG. 8 illustrates a portion of an example power-line communicationssystem 10 including an example surge arrester 16, an example disconnectdevice 50, an example parallel bypass 60 including bypass capacitor 62,and an example coupler 20, according to a particular embodiment. Asshown, in certain embodiments, parallel bypass 60 may conductivelyconnect between surge arrester 16 and disconnect device 50. In theembodiment shown, parallel bypass 60 connects to coupler 20, which, inturn, couples to both low-voltage communications line 26 and disconnectdevice 50. As discussed further in relation to FIGS. 9 and 10, incertain embodiments, variations of coupler 20 (such as coupler 120) mayinclude bypass capacitor 62. In operation, capacitor 62 may provide alow-impedance bypass around disconnect device 50 for certainfrequencies. In certain embodiments, one or more of surge arrester 16,disconnect device 50, parallel bypass 60, bypass capacitor 62 andcoupler 20 may be included within a single component. Similarly, one ormore of the functions provided by surge arrester 16, disconnect device50, parallel bypass 60, bypass capacitor 62, or coupler 20 may be servedby multiple components.

FIG. 9 illustrates a circuit diagram of an example medium-voltage powerline disconnect device 50. As shown, disconnect device 50 may functionas a resistor 52 in parallel with an air gap 54. In operation, ahigh-voltage spike may result in a spark across air gap 54, which mayignite a gun-powder charge to disconnect surge arrester 16 fromconductor 22. Resistor 52 may represent any component or group ofcomponents that operate to provide a resistance to an electricalcurrent. For example resistor 52 may represent a grading resistor. Incertain embodiments, due to the presence of resistor 52, disconnectdevice 50 may limit the transmission efficiency for communicationssignals between medium-voltage power lines and communications device 16.

FIG. 10 illustrates a circuit diagram of an example medium-voltage powerline disconnect device 50 with an example parallel bypass 60 includingbypass capacitor 62, according to a particular embodiment. In certainembodiments, to improve the transmission efficiency for thecommunications signal coupling, a parallel bypass 60 may be utilized.Parallel bypass 60 may broadly represent a circuit path in parallel withdisconnect device 50. For example, parallel bypass 60 may be a copperwire conductively coupled between surge arrester 16 and disconnectdevice 50. In certain embodiments, as shown in FIG. 10, parallel bypass60 may include capacitor 62. Capacitor 62 may broadly represent one ormore components operable to provide capacitance for parallel bypass 60.For example, in a particular embodiment, capacitor 62 may represent aceramic disk capacitor, such as a 1000 picofarad, 3 kV capacitor.

FIG. 11 illustrates a circuit diagram of a portion of an examplepower-line communications system 10, including an example disconnectdevice 50 and an example parallel bypass 60 including bypass capacitor62, according to a particular embodiment. In the embodiment shown,communications device 18 is connected to neutral line 14, throughconductor 28, and to coupler 20. In the embodiment shown, coupler 20 isconnected to surge arrester 16 through disconnect device 50 in parallelwith parallel bypass 60. Coupler 20 may or may not include componentsproviding an impedance matching function.

FIG. 12 illustrates a component diagram of an example configuration ofcoupler 120, a variation of coupler 20 including a bypass capacitor 62.As shown, in certain embodiments, coupler 120 a may include base 40,bypass capacitor 62, and connectors 42, 44, and 90. Connector 90 maybroadly represent a connector for electrically coupling parallel bypass60 to coupler 120 a. Thus, connector 90 may represent any appropriatehardware for electrically coupling to parallel bypass 60. In theembodiment shown, capacitor 62 is connected in series between connector90 and connector 44.

FIG. 13 illustrates a component diagram of an example configuration ofcoupler 120, a variation of coupler 20 including a bypass capacitor 62.As shown, in certain embodiments, coupler 120 b includes both a bypasscapacitor 62 and impedance matching components. In the embodiment shown,coupler 120 b includes bypass capacitor 62, connected in series withconnector 90, and impedance transformer 30 and capacitor 32, connectedin series with connector 42. In this embodiment, coupler 120 b mayoperate to couple communications device 18 to medium-voltage power line12 with improved efficiency by bypassing disconnect device 50 and bymatching impedances between medium-voltage power line 12 andcommunications device 18.

FIG. 14 illustrates a portion of an example power-line communicationssystem 10 including an example surge arrester 16, an example disconnectdevice 50, an example parallel bypass 60, and an example coupler 120,according to a particular embodiment. As shown, in certain embodiments,parallel bypass 60 may conductively connect between surge arrester 16and disconnect device 50. In the embodiment shown, parallel bypass 60connects to coupler 20, which, in turn, couples to both low-voltagecommunications line 26 and disconnect device 50. In the embodiment shownin FIG. 14, unlike the embodiment shown in FIG. 8, parallel bypass 60does not include bypass capacitor. Rather, in this embodiment, thebypass capacitor 62, if any, is included as a component of coupler 120.

FIG. 15 illustrates a circuit diagram of a portion of an examplepower-line communications system 10, including an example disconnectdevice 50 and an example parallel bypass 60, according to a particularembodiment. In the embodiment shown, communications device 18 isconnected to neutral line 14, through conductor 28, and to coupler 120.In the embodiment shown, coupler 120 is connected to surge arrester 16through disconnect device 50 in parallel with parallel bypass 60. In theembodiment shown in FIG. 15, unlike the embodiment shown in FIG. 11,parallel bypass 60 does not include bypass capacitor. Rather, in thisembodiment, the bypass capacitor 62, if any, is included as a componentof coupler 120. In certain embodiments, although not necessary, coupler120 may include both a bypass capacitor 62 and impedance matchingcomponents.

Although the present invention has been described with severalembodiments, a plenitude of changes, substitutions, variations,alterations, and modifications may be suggested to one skilled in theart, and it is intended that the invention encompass all such changes,substitutions, variations, alterations, and modifications as fall withinthe spirit and scope of the appended claims.

1. A system for communicating signals over a medium-voltage power line,the system comprising: a communications device comprising at least onemodem; and a coupler comprising: a coaxial connector coupled to thecommunications device; an impedance transformer electrically coupled tothe coaxial connector, the impedance transformer having a step-up ratioof approximately 8:1; a capacitor electrically coupled to the impedancetransformer, the capacitor having a capacitance of approximately 0.05microfarads; a conductive metallic disk electrically coupled to thecapacitor, the conductive metallic disk defining a substantiallycircular opening adapted to accept a ground post from a lightningarrester; and a circuit board, wherein the connector, the capacitor, theimpedance transformer, and the conductive disk are coupled to thecircuit board.
 2. A system for communicating signals on a medium-voltagepower line, the system comprising: a communications device; and acoupler comprising: a first connector adapted to couple to thecommunications device; an impedance transformer; a capacitor; and asecond connector defining an opening adapted to accept a ground postfrom a surge arrester; wherein the impedance transformer and thecapacitor are coupled between the first connector and the secondconnector such that signals communicated between the communicationsdevice and the surge arrester pass through the impedance transformer andthe capacitor.
 3. The system of claim 2, wherein the first connector isadapted to couple to a coaxial cable having an impedance ofapproximately 50-75 ohms.
 4. The system of claim 2, wherein theimpedance transformer provides a step-up ratio in the range from 5:1 to9:1.
 5. The system of claim 2, wherein the capacitor provides acapacitance in the range from 0.01 to 0.1 microfarads.
 6. The system ofclaim 2, wherein the second connector comprises a metallic disk.
 7. Thesystem of claim 2, wherein the opening has a diameter in the range from0.25 to 0.75 inches.
 8. The system of claim 2, wherein: the couplerfurther comprises a circuit board; and the first connector, thecapacitor, the impedance transformer, and the second connector arecoupled to the circuit board.
 9. A device for coupling communicationssignals to a medium-voltage power line, the device comprising: a firstconnector adapted to couple to a low-voltage communications line; animpedance transformer; a capacitor; and a second connector adapted tocouple to a surge arrester; wherein the impedance transformer and thecapacitor are coupled between the first connector and the secondconnector such that signals communicated between the low-voltagecommunications line and the surge arrester pass through the impedancetransformer and the capacitor.
 10. The device of claim 9, wherein thelow-voltage communications line comprises a coaxial cable having animpedance of approximately 50-75 ohms.
 11. The device of claim 9,wherein the impedance transformer provides a step-up ratio in the rangefrom 5:1 to 9:1.
 12. The device of claim 9, wherein the capacitorprovides a capacitance in the range from 0.01 to 0.1 microfarads. 13.The system of claim 9, wherein the second connector comprises a metallicdisk which defines a substantially circular opening with a diameter inthe range from 0.25 to 0.75 inches.
 14. The device of claim 9, furthercomprising a circuit board; wherein the first connector, the capacitor,the impedance transformer, and the second connector are coupled to thecircuit board.
 15. A device for coupling communications signals to amedium-voltage power line, the device comprising: a base; one or moreelectrical components; a first connector adapted to couple to alow-voltage communications line; and a second connector adapted toconductively couple to a surge arrester, the second connector defining asubstantially circular opening adapted to accept a ground post from thesurge arrester; wherein the one or more electrical components, the firstconnector, and the second connector are physically coupled to the base.16. The device of claim 15, wherein the base comprises a circuit board.17. The device of claim 16, further comprising a protective coatingcovering at least a portion of the circuit board, the protective coatingadapted to seal the at least a portion of the circuit board againstmoisture.
 18. The device of claim 15, wherein the one or more electricalcomponents are operable to provide impedance matching.
 19. The device ofclaim 15, wherein the second connector comprises a metallic disk. 20.The device of claim 15, wherein the substantially circular opening has adiameter in the range from 0.2 inches to 0.8 inches.
 21. The device ofclaim 15, wherein the substantially circular opening has a diameter of0.4 inches.
 22. A device for coupling communications signals to amedium-voltage power line, the device comprising: a first connectoradapted to couple to a low-voltage communications line; a secondconnector adapted to couple to a surge arrester; and one or morecomponents operable to substantially match the impedances between thesurge arrester and the low-voltage communications line; wherein the oneor more components are coupled between the first connector and thesecond connector such that signals communicated between thecommunications device and the surge arrester pass through the one ormore components.
 23. The device of claim 22, wherein the one or morecomponents comprise an impedance transformer having a step-up ratio inthe range from 5:1 to 9:1 in series with a capacitor having acapacitance in the range from 0.01 to 0.1 microfarads.
 24. The device ofclaim 22, wherein the low-voltage communications line comprises acoaxial cable.
 25. A method for coupling communications signals to amedium-voltage power line, the method comprising: transmitting acommunications signal: from a signal regenerator through a low-voltagecommunications line; from the low-voltage communications line throughone or more components operable to increase impedance by a ratio ofbetween 5:1 and 9:1 and to substantially match the impedances between asurge arrester and the low-voltage communications line; from the one ormore components through the surge arrester; and from the surge arresterto a medium-voltage power line.
 26. A device for coupling communicationssignals to a medium-voltage power line, the device comprising: a firstmeans for coupling to a low-voltage communications line; a second meansfor coupling to a surge arrester; and a means for substantially matchingthe impedances between the surge arrester and the low-voltagecommunications line; wherein the means for substantially matching theimpedances is coupled between the first means and the second means suchthat signals communicated between the low-voltage communications lineand the surge arrester pass through the means for substantially matchingthe impedances.